274 PYRAMIDELLID^. 



niitted to this species, the spire being sometimes stunted, 

 at other times very considerably produced. It is glossy, 

 sometimes thin and slightly transparent, sometimes opaque 

 and solid, of a milk-white hue, and either smooth or 

 merely microscopically striolated in a spiral direction. A 

 rare variety, however, adorned with regular spiral cos- 

 tella?, has been taken in Gahvay. There are six convex 

 and well defined whorls, that are more slanting above, more 

 perpendicular and rounded below, of rather quick longi- 

 tudinal increase, and often shghtly shouldered. The pe- 

 nult turn, viewed dorsalfy, is almost equal to the rest of 

 the spire : the apex is rather blunt. The suture is simple, 

 though well marked, and is more or less oblique. The 

 body, which is not at all swollen, but more usually is flat- 

 tened in the middle, is in general rather longer than the 

 spire ; the latter, however, slightly exceeds the former in 

 some large individuals we have taken in the Channel 

 Islands ; there is usually a slight attenuation of the base, 

 whose declination is gradual and somewhat convex. The 

 mouth, which is a little disposed to expand, occupies 

 nearly one-half the length of the shell, is of an elongated 

 oval figure, acuminately contracted above, and rounded, 

 though not broadly so, at the somewhat effusely produced 

 base. The outer lip is simple, acute, and more or less 

 arcuated : the throat is quite smooth. The much elon- 

 gated and scarcely curved pillar lip is broadly reflected and 

 furnished with a more or less strong, though retired, fold 

 (the amount of whose development seems variable), which 

 is not centra], but lies much nearer to the upper or nar- 

 rower extremity of the aperture. There is no distinct 

 umbilicus, but a more or less manifest chink, and a linear 

 indentation behind the pillar lip. The ordinary length of 

 examples is only the fifth of an inch, but they sometimes 



